Items of currency wear out and must be replaced. In The Mechanism of Exchange, Jevons recommended that the government bear the cost of replacing worn gold coins with new coins instead of having the holders of worn coins bear the cost. We study the optima of a minimally interesting model: money is essential and indivisible so that physical depreciation is not neutral; and there are alternative ways of financing the costly replacement of worn currency. The optima contradict the Jevons proposal. People with worn currency bear a cost that makes them indifferent between getting a new unit and discarding the useless worn unit, a cost that exceeds the physical cost of replacement.

中文翻译：

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最优地提供昂贵的货币

货币项目磨损，必须更换。杰文斯在《交易机制》中建议政府承担用新硬币代替旧金币的费用，而不是让旧币的持有人承担费用。我们研究了一个最小有趣模型的最优：金钱是必不可少且不可分割的，因此物理折旧不是中性的。还有其他方法可以为昂贵的旧币更换提供资金。这种最佳做法与Jevo​​ns的提议相矛盾。货币疲软的人承受的成本使他们在获得新的设备和丢弃无用的磨损的设备之间变得无动于衷，该成本超过了更换的实际成本。